Track and wayside detectors
BNSF uses a range of sophisticated detection equipment on its network to keep trains operating safely.
A railroad track consists of steel rails, ties and ballast. The ties hold the rails in position; in the U.S. the gauge, or distance between the rails, is 56.5 inches. Most BNSF ties are wood, but concrete ties are also used.
The rails are restrained from moving by anchors on wood ties and elastic clips on concrete ties. If they weren't restrained, a 100-degree temperature change in the rails (a common occurrence over the course of a year) could cause the network to grow or shrink up to 25 miles due to expansion and contraction.
BNSF uses ballast made up of crushed rock to keep the track structure stable and well drained.